1 sediment southwestward to a depositional area south of Martha's 



2 Vineyard, shown in that purple area. 



3 We're going to be looking at the region on the southwest margin of 



4 the bank. In this area here, where we have several canyons of varying 



5 sizes and some study areas on the shelf and upper slope and outer shelf 



6 near the canyons. 



7 This shows our main areas of interest here, it includes large 



8 canyons such as Oceanographer and Gilbert, medium-sized canyon Lydonia, 



9 a small canyon called Heeltapper Canyon over here, and several 



10 shelf/slope areas. One of the shelf/slope areas is near Filebottom 



11 Canyon and the other is to the west of Heeltapper Canyon. 



12 Now, the color code here yellow represents a high-energy 



13 environment, broadly speaking, the blue is moderate energy and the 



14 purple represents a low-energy sedimentary environment. 



15 Before I go on, I'd like to enumerate the sorts of sedimentary 



16 environments we're going to be looking at. One of the areas we are 



17 going to be looking at is in the region of the upper slope. 



18 We're going to be looking at a region of the upper slope here 



19 where we have an erosional band along the upper slope caused by the 



20 erosive activity of warm-core ring currents. That occurs in this area 



21 and also over here. 



22 Below that in the gullied part of the upper slope is a 



23 depositional area where we have accumulation of fine-grained sediments. 



24 The canyon rim sediment is transported across the canyon rims into the 



25 canyons on all sides, but in particular on the eastern rims of several 



26 of these canyons there's increased current activity and the more 



27 vigorous sediment transport. 



28 The walls of the canyons, to varying degrees, are undergoing 



29 bioerosion from crabs and fish, as was demonstrated in Dick Cooper's 



30 video tape. 



31 Around the heads of the canyons there are areas of deposition of 



32 fine-grained sediment and the canyon axes also vary in character of 



33 sedimentary environment from very vigorous--from deposits of course sand 



34 that are subjected to very vigorous currents, from which the fines are 



35 



